The present inventor has priorly proposed a roll toothbrush favorable for removing plaque deposited onto teeth and for massaging of gums, and a manufacturing method therefor (Japanese Published Unexamined Patent Application No. H12-83736). With this roll toothbrush, one end of a wire group formed by assembling a plurality of wires of nylon, etc., together in a bundle is heat welded to form a semispherical welded part, and this welded part is thereafter flattened by pressurizing. A part of the flattened part to become an axial hole is then cut out and pressurized further to make the entirety of the wire group and the flattened part substantially circular. The ends of the flattened part are then joined together by welding, etc., thereby forming an annular part, and a sheet-like brush unit is thus prepared. By then connecting a plurality of the brush units obtained in this manner by joining the annular parts of the brush units, a roller-like rotary brush is formed. This rotary brush is supported rotatably via a supporting shaft at one end of a handle member, thereby arranging a roll toothbrush.
Since the rotary brush manufactured in the above manner requires expertise in making the thickness of the annular part thereof uniform and making the bristle density of the rotary brush uniform and requires processes difficult to mechanize, consistent and continuous manufacture is difficult to realize and thus mass production is difficult and the manufacturing cost is high.
The present invention thus improves on the above proposition, and an object of the present invention is to provide a method and a device for manufacturing a rotary brush for use in a roll toothbrush, and a roll toothbrush, which enable the bristle density of the rotary brush to be made uniform, thereby providing excellent effects in removing plaque deposited onto teeth and massaging of gums, and yet enable cost reduction.